A special pose used by women while taking photographs in an effort to reduce the appearance of arm fat. It is performed by standing at an angle towards the camera, with the exposed arm in an akimbo position. Typically, photos such as these appear on Facebook and dating websites. Also typically, the women who strike such a pose are fat and/or insecure about their body image.

Girl: Hey girls, let's all take a group photo
Guy: Wow look at those fatties using the arm triangle of insecurity, all at the same time.
Girl: Omg, we look amazing!